Automatic custody transfer system



Nov. 29, 1966 L. H. HUGHES AUTOMATIC CUSTODY TRANSFER SYSTEM 2 Sheets-Sheet 1 Filed May 11, 1964 Nov. 29, 1966 L. H. HUGHES AUTOMATIC CUSTODY TRANSFER SYSTEM 2 Sheets-Sheet 2 Filed May 11, 1964 United States Patent AUTOMATIC CUSTODY TRANSFER SYSTEM Leonard H. Hughes, Dallas, Tex., assignor to Texaco Inc., New York, N.Y., a corporation of Delaware Filed May 11, 1964, Ser. No. 366,472 Claims. (Cl. 73219) This is a continuation-in-part of copending application Ser. No. 128,830, filed August 2, 1961 now abandoned.

This invention relates to an automatic custody transfer system, and more particularly is concerned with such a system for measuring or metering petroleum liquid, e.g. crude oil.

It is an object of this invention to provide an automatic custody transfer system for accuately measuring or metering oil well production prior to transfer of the oil to the pipeline for sale.

It is another object of the invention to provide a system of the above type which is automatic, simple and eco nomical in design and structure, and which eliminates any false measurements or spurious counts;

Still another object of the invention is to provide an improved automatic custody transfer system which obtains some of the benefits of prior known structures in a more facile manner.

These together with other objects and advantages of the present invention will best be understood by referring to the following detailed specification and preferred embodiment thereof, and the accompanying drawings.

In the drawings:

FIGURE 1 is a vertical sectional view through metering apparatus constructed in accordance with the present invention;

FIGURE 2 is an electrical circuit diagram illustrating the control system employed in connection with the elements illustrated in FIGURE 1;

FIGURE 3 is an enlarged elevational view showing details of the metering counter employed in the system of this invention;

FIGURE 4 is an enlarged elevational view showing the structure of the cam employed in the metering counter illustrated in FIGUREE 3; and

FIGURES 5, 6, and 7 are additional views of the cam of FIGURE 4 showing advanced positions.

In general, the automatic custody transfer system of the present invention includes a cylindrical tank divided into three fluid-tight chambers by means of a pair of spaced members, preferably fiat planar members thereby avoiding entrapment of air in the chambers. The spaced members are substantially transverse to the side walls of the cylindrical tank thereby providing an upper chamber, an intermediate chamber and a lower chamber. Also these flat planar members are sloped steeply enough to provide Seraphin neck action near the top of the intermediate chamber. There is an inlet leading into the upper chamber for conveying oil thereto, and an outlet from the lower chamber for discharging the oil from the tank to a pipeline. Conduit means for providing passage of the liquid oil establishes communication between the upper chamber and the intermediate chamber and between the intermediate chamber and the lower chamber. Valve means is provided for controlling the flow of liquid between the upper and middle chambers and between the middle and lower chambers. The valve means preferably is power-actuated and desirably of the three-way type. The valve means is constructed and arranged so that when in one position, communication is opened between the upper chamber and the intermediate chamber and communication is closed between the intermediate chamber and the lower chamber. When the valve means is shifted to a second position, communication is opened ice between the intermediate chamber and the lower chamber while communication between the upper chamber and the intermediate chamber is closed. A neutral position of the valve means closes communication between the respective chambers. Control means operates the valve means in a cyclic manner whereby the intermediate chamber is open to communication with the upper chamber when the valve means is in a first position, allowing the oil accumulated in the upper chamber to flow by gravity into the intermediate chamber to fill the latter. When the intermediate chamber is filled with oil, control means actuates the valve means to open communication between the intermediate chamber and the lower chamber while closing communication between the upper chamber and the intermediate chamber, whereby the oil is permitted to drain by gravity flow from the intermediate chamber into the lower chamber. The intermediate chamber is filled and drained during one complete cycle, and a suitable counter means, preferably actuated by the control is provided for counting and recording the number of times the intermediate chamber is filled.

Referring to FIGURE 1 of the drawings, crude oil enters a heater treater, indicated generally by the numeral 2, via inlet conduit 4 from a separator or other source (not shown). Gas and bottom sediments and water (referred to as BS and W) commonly present in crude oil may be removed from the crude oil in the heater treater by conventional means, or the crude oil may be otherwise conditioned for metering and pipeline delivery.

The preconditioned crude oil is passed from the heater treater 2 through a heat exchanger 5 to heat fresh charge, and then to cylindrical tank 6 via conduit 8. Conduit 8 is provided with a regulator flow valve 9 for controlling the fiow of fluid from the heater treater to tank 6. A pump (not shown) of any suitable type may be provided in conduit 8 to facilitate flow of oil from treater 2 to tank 6. Crude oil enters near the top of tank 6 which is provided with two spaced plate members 10 and 12. The plate members are in a sloping position transverse to the side walls of the tank, and preferably parallel to each other. The slope of these fiat planar members is sufficiently steep to provide Seraphin neck structure between the upper edge of the member and the side of the tank that is adjacent thereto. In this manner, tank 6 is divided into three fluid-tight chambers, i.e. an upper chamber, an intermediate chamber and a lower chamber, designated as chamber A, B and C, respectively.

Crude oil conveyed from the heater treater 2 enters the tank near the top of upper chamber A, which serves as a surge for storage of treated crude oil to be metered for pipeline delivery or sale. The upper chamber may be provided with a suitable vent 14 which desirably connects back to the heater treater to return any oil resulting from an overflow as may occur on failure of the controls. Intermediate chamber B of known capacity or volume, serves as a metering receptacle or tank for measuring the quantity of oil transported to the pipeline for delivery or sale. The lower-most chamber C, desirably having a sloping bottom deck 15, serves as a sump for the metered oil, and is provided with a suitable vent 16 and an outlet line 17 for conveying the oil to the pipeline.

Manifold piping, indicated generally at 18, provides fluid communication between the three fluid-tight chambers of tank 6. A three-way valve 20, suitably a motor actuated valve, interposed in manifold 18, is adapted to alternatively place chamber A in communication with chamber B, and chamber B in communication with chamber C. Thus, with the valve 20 in one position, fluid communication is established between chamber A and chamber B, there being no communication open to cham- 3 ber C. When valve 29 is actuated to a second position, communication is established between chamber B and chamber C while concomitantly interrupting or breaking communication between chamber A and chamber B.

Discharge line 22 and flow line 24 of manifold 18 are positioned just above the lowest horizontal points of each of the transverse sloping plate members and 12, respectively. Branch line 25 opens to float box or receiver 26, and line 27 leading from the float box opens to chamber C. Line 27 preferably extends in an upward direction from the float box such that line 27 opens to chamber C at a point higher than the top of float box, as seen in FIGURE 1. The float box 26 is also provided with line 28 which leads from the bottom of the float box to chamber C. As compared to lines 25 and 27, line 28 is relatively small in cross-section, or line 28 may be constricted to limit its capacity.

Float chamber 29, having float switch 30, is in fluid communication with metering chamber B through pipe 31 which extends from near the top portion thereof desirably to a distance substantially above the top of chamber A which also serves as a vent means for chamber B. The float chamber 29 is provided with a suitable float switch 30 or other suitable liquid level responsive device for indicating that chamber B has been filled with oil, and serves to actuate valve through electric circuit means 33 described below in greater detail. Top float chamber 29 is located at a level above the uppermost point of the transverse sloped plate member 10 and therefore at a point above the full liquid level of chamber B. A second suitable liquid level float switch 32 is arranged in float box 26 which is interposed in branch line of manifold 18. Float control 32 indicates when chamber B is empty, and also is adapted to actuate valve 20 through electric circuit means 33 as explained below.

The float control switches and 32 are normally in the down position, and the three-way valve 20 fluidly communicates chamber A with chamber B via lines 22 and 24 of manifold conduit means 18. When the .valve 20 is opened to this position, crude oil which has accumulated in chamber A of tank 6 is drained into chamber B by gravity flow. The oil rises in chamber B and enters float chamber 29. The rise in liquid level continues until it deflects float switch 30 to the up position which is electrically connected through a suitable circuit means 33 to actuate three-way valve 20 as explained below in greater detail, interrupting the flow of oil into chamber B which is now full and establishing communication between chamber B and chamber C via lines 24, 25, float box 26 and line 27, and the crude oil from chamber B is transferred or drained into chamber C. In operation, the oil flows rapidly into float box 26, and because line 28 is of restricted cross-section, the float box fills and overflows into chamber C primarily via line 27. The rise of oil in the float box deflects float switch 32 to the up position. When chamber B is empty, the level of 'liquid in the float box drops. Oil remaining in the float box is drained therefrom via line 28 into chamber C. Upon substantial draining of float box 26, float switch 32 is deflected to the down position and thereby actuates the three-way valve 20 by electrical circuit means to close the valve and interrupt further draining from chamber B. Each of the separate chambers is desirably provided with a transverse sloping plate as a bottom deck to facilitate draining, as illustrated. However, the flat planar members 10 and 12 .are steeply sloped in order to provide a Seraphin neck at the top of chamber B, as indicated above. Also the plate member 12 is preferably parallel to plate member 10 in order to facilitate easy and compact connections for carrying out the measuring cycles indicated. Outlet conduit 17 from chamber C, having pump 38, conveys the crude oil to the pipeline.

Positioned in manifold piping 18 is a monitoring probe 40 of any suitable type. In the event the monitoring probe 40 indicates an excessive or undesirable quantity of BS and W, the three-way valve is actuated to a closed or neutral position by electric circuit means '33 as dew scribed below to prevent communication between any of the chambers, and the crude oil is returned to the heater treater via return lines 42 and 44 by pump 46 for further conditioning or treatment. The monitoring unit, per se, forms no part of the invention, and various types for accomplishing this check are available on the market and may be employed in the system.

Oil delivered to chamber B may be sampled by sampler 48. Samples taken may be conducted via conduits 50 and 52 to a small sampling container 54 where these are comingled to provide a composite of all the oil metered for a determinate period of time. Pneumatic switch 56 is actuated by the fluid head in the metering chamber B and stops the sampling procedure when chamber B is filled but before float switch 30 is deflected to the up posi-.

float chamber 29. The cross-section of float chamber 29 is relatively small in comparison to the volumes of chamber A and chamber B, and therefore the quantity of oil required to actuate the float switch 30 is small. Consequently, a relatively large volume of oil flows into chamber A in order to raise the level of liquid in float chamber 29 suflicient to deflect the float switch 30. The movement of the oil level in chamber 29 is very slow in reaching the level where it operates float switch 30 thereby resulting in an accurate cutofl level. It therefore will be observed that by reason of pneumatic switch 56 stopping the sampling procedure when chamber B is filled (when the neck at the top of the measuring chamber by reason of the reduced cross section area created between the side wall of the tank 6 and the adjacent portion of the planar member 10. This structure facilitates the accurate cut off and slow rise action described above.

There is also provided a chart recorder 59 that is permanently connected to probe 60 inserted in metering chamberB and continuously records the temperature and static pressure at or near the bottom of the chamber.

The pressure indication provides a means for checking the number of metered volumes which have been made during any recording period, and the temperature in the chamber B indicates the average temperature of the .oil that was metered.

In FIGURE 2, there is shown a suitable electrical circuit arrangement for controlling the operation in proper sequence, the connections being indicated by the broken lines in FIGURE 1, but other suitable designs may be employed. Electrical power from a suitable source, such as a volt A.C. current, is fed to the system at the input terminals (one of which is grounded) indicated generally at 62. The circuit employs two double-pole, double throw switches or contacts, 64 and 66, and 68 and 70, actuated by a mechanical connection driven by motor 72 as indicated by the broken line 73 in FIGURE 2.

fill position such that oil may flow by gravity into chamber B from chamber A. Upon completion of this fill cycle, the float switch 30 is deflected up and actuates contact 74 to the second closed position (upper position in FIGURE 2) thereby de-energizing the solenoid 78 which actuates the valve 20 to the neutral position to close fluid passage between chamber A and chamber B. Simultaneously therewith, the circuit is closed through contacts 68 and 66 to energize motor 72 which drives rotating shaft 80 having mounted thereon a revolution counter 82 and a cam 84, explained hereinafter in more detail. (See FIGURE 3;) Energizing motor 72 advances the counter and also rotates the cam 84 in the direction indicated by the arrow. (See FIGURES 4 through 7.) It will be observed that rotation of the cam from the start position as shown in FIGURE 4 to the position shown in FIGURE 5 actuates contacts 64 and 66 to the second position (to the right in FIGURE 2) thereby breaking the electrical circuit so as to deenergize the motor and stop any further revolution of the counter. Actuation of contact 64 to the second position energizes solenoid 86. This in turn actuates the three-way valve 20 to permit draining from chamber B into chamber C. As explained above, oil flows rapidly in float box 26 and because draining therefrom is limited by reason of the relatively small cross-section of line 28, oil rises in the float box and deflects float switch 32 to the up position. A major portion of the oil passes to chamber C via line 27 thereby retaining float switch 32 in the up position. As a result, electrical circuit is established through contacts 76, 70 and 66 (now in the second position) and energizes the motor thereby again rotating the counter 82 and cam 84. However,

this additional rotation of the cam (FIGURE 6) actu-' ates contacts 68 and 70 to the second position (to the right in FIGURE 2) thereby breaking the circuit and de-energizing the motor. When chamber B is completely drained, oil in the float box 26 passes to chamber C via conduit 28 until float switch 32 is deflected to the down position (the original position). This actuates contact 76 to the original position and as a consequence the motor is again energized through contacts 70 and 66, both being in the second position. The counter is advanced, and the cam is rotated to the position shown in FIGURE 7 where it again actuates contacts 64 and 66 to return these contacts to the original position whereby solenoid 86 is de-energized. By reason of the draining step, float switch 30 is in the down position, and contact 74 is in its original position. As a result, the electric circuit established through 64, 66 and 74 (all now r in their original position) and 68 (in the second position) energizes the motor. In addition, solenoid 78 is energized which actuates valve 20 and opens fluid communication between chamber A and chamber B. The motor rotates the counter, and simultaneously, the cam, until rotation of the cam again actuates contacts 68 and 70 to their original position (FIGURE 4) thereby de-energizing the motor and stopping the counter advance. This completes one full revolution of the cam, and all parts are returned to the original position to begin a second cycle. The configuration of the cam is preset so that chamber B is filled and drained during one complete cycle, and the counter is advanced to register one unit.

Where desired, valve 87 (see FIGURE 1) may be interposed in line 28 and actuated by the circuit control means in proper sequence. When three-way valve 20 is opened to permit draining of oil from chamber B to chamber C, valve 87 is also opened to permit passage of oil from float box 26 to chamber C via line 28. However, when valve 20 is actuated by reason of the full drained condition of chamber B and thereby interrupting communication into chamber C, valve 87 is also closed to stop further draining of oil from float box 26. Thus, the level of oil in float box 26 is at the level of the float switch 32 in the down position. As a consequence, at the start of another drain cycle when the oil is drained from chamber B to chamber C, oil is present in float box 26 and a small additional quantity only is necessary to deflect the float switch 32 to the up position to further continue the cycle. In this manner, a shorter lapse in time is involved in deflecting the float switch 32 than if the drain cycle began with the float box fully drained. This is true notwithstanding the small diameter of line 28 to limit or restrict the rate of flow therethrough.

Valve 87 is particularly important also in that it prevents short cycling in the event of electrical power failure. The term short cycling is defined as delivery of only a portion of the metered volume to the pipeline before chamber B begins filling again. By way of illustration, assume there occurs an electrical power failure during draining of'chamber B, and as a consequence, valve 20 shifts to the neutral position. If line 28 were not provided with valve 87, the oil in float box 26 would drain therefrom into chamber C, and float switch 32 would be deflected to a down position thereby indicating a full drained condition for chamber B. Upon restoration of the power, chamber B would begin filling, and consequently resulting in short cycling. However, valve 87 prevents this. Thus, in the event of a power failure, valve 87 would close thereby preventing float box 26 from completely draining, and float switch 32 would remain in the same position. Upon restoration of power, operations would resume from where they left off thereby preventing any short cycling or spurious counts.

Referring now to FIGURES 3, 4, 5, 6 and 7, there is shown further details of the motor arrangement, the counter, and the cam actuating means, suitably mounted in a housing 88, preferably an explosion-proof housing. Motor 72, desirably a standard type induction gear motor, having an output shaft speed of about /3 rpm. and having a coil 90 mounted on an armature 92, drives rotating shaft 80. A counter 82 of conventional design and structure and a cam 84 are mounted on shaft 80, as illustrated. The aforementioned double-pole, doublethrow contacts 64, 66 and 68,70 may be positioned in a suitable housing 94, and actuated by means of spring biased actuator 96 or 97 which bears against the marginal edge surface of the cam 84. When the motor 72 is energized, the counter is advanced and the cam is rotated in the direction indicated by the arrows by means of rotation of the shaft.

In operation of the illustrated specific embodiment of the metering system of the present invention, crude oil from the field having been preliminarily conditioned in heater treater 2, enters near the top of upper chamber A of tank 6. The three-way valve 20 is opened as explained above, to allow the oil accumulated in chamber A to flow by gravity from that chamber through the manifold 18 and into intermediate metering chamber B. Samples of oil are withdrawn as the oil is delivered to chamber B by means of sampler 48. In the event that the BS and W content of the oil from chamber A is undesirably high, as determined by probe 40, switch 41 of electric circuit means 33 is opened, de-energizing solenoid 78 and returning valve 20 to a neutral position. At the same time, probe 40 energizes pump 46 to return the contaminated oil to treater 2 for further conditioning. When chamber B is completely filled, pneumatic switch 56 which has been adjusted to be actuated by a predetermined fluid head in chamber B, desirably at 58, is actuated to stop the sampling. A composite of the crude oil material is stored in sampling container 54. The static pressure near the base of chamber B and the temperature of the oil for each metered volume are recorded on chart 59.

Crude oil continues to flow from the heater treater 2 via conduit 8 into surge chamber A and from there into chamber B until the rise in liquid level in float chamber 7 29 deflects float switch 30. This in turn actuates contact 74 to open the electric circuit to the solenoid 78 whereby the solenoid is de-energized and the three-way valve 20 is shifted to the neutral position to interrupt fluid passage from chamber A to chamber B, and motor 72 of electric circuit 33 is started.

As explained above, particularly with reference to the schematic diagram FIGURE 2, the three-way valve 20 is actuated by the electric circuit means to provide fluid communication between chamber B and chamber C. The oil in chamber B thus is drained into chamber C. When chamber B is empty, the liquid level in float box 26 deflects float switch 32 thereby actuating contact 76. The

electric circuit is again closed to energize the motor. The I counter 82 is advanced, and the cam 84 rotates until contacts 64 and 66 are actuated to the original position. However, the electrical circuit is closed through contact 74 to continue the advances of the counter and rotation of the cam until the cam actuates contacts 68 and 70 to break the circuit. This completes the cycle registering one unit on the counter, and the system is ready for another cycle. The crude oil from chamber C is transported to the pipeline via conduit 17 through pump 38.

It will be observed from the present invention that the counter advances a small fraction of a revolution only during any part of the flow of oil into or from the metering chamber B. Thus, the major portion of the revolution is recorded by the counter after the crude oil is drained from metering chamber B into sump chamber C and is, in fact, flowing to the pipeline. In the preferred embodiment of the present invention, the configuration of cam 84 is such that upon deflection of the float switch 30 to the up position by reason of chamber B being filled and thereby energizing the motor (as explained above), the counter is advanced ,5 of a revolution until the motor is stopped upon actuation of contacts 64 and 66. However, the electric circuit thus established, which opens the draining means, again energizes the motor and advances the counter an additional of a revolution until actuation of contacts 68 and 70 open the circuit. The motor is not energized further until float switch 32 is deflected down to the original position indicating that chamber B is empty. When this occurs, cam 84 is rotated until it again actuates contacts 64 and 66, which is through the greatest part of its rovolution. As a consequence, the counter is advanced A of a revolution. The closed electrical circuit thus established through contacts 64, 66 and 74 (now in the original position) and contact. 68 (still in the second position) energized the motor to advance the counter the remaining of the revolution, thereby recording one unit. Thus, the major portion of the recording on the counter occurs after the oil is drained from the metering chamber B. This is particularly advantageous in the event there is a power failure or a breakdown of controls and thereby prevents the possibility of spurious counts.

As an additional preferred embodiment of my invention, the volume of chamber A is not less than 1 /2 times the volume of chamber B. Thus, at least /3 of the crude oil drained from chamber A into chamber B during a fill cycle remains in chamber A and is not drained therefrom until the next succeeding cycle. For beginning that next cycle, chamber A is filled, and upon subsequent draining into chamber B that portion of crude oil which remained in chamber A upon completion of the first cycle constitutes at least /2 of the metered volume of the second cycle. In this manner, one metered volume will always be weathered in chamber A through one cycle, and at least a 50% metered volume will always be weathered through two cycles. The additional weathering treatment may be particularly advantageous in order to permit the escape of any undesirable excess gas present in the oil which may not have been removed during the preconditioning treatment.

While preferred embodiments of the invention have been described above in considerable detail, this is not to be taken as in any way limiting the invention, but merely as being descriptive thereof.

I claim:

1. An automatic custody transfer system comprising,

a cylindrical tank; a first transverse planar flat plate mem-' ber sloping sufficiently from the horizontal when said tank stands vertically to form a Seraphin neck and .di-

viding said tank into an upper chamber thereaboveya second transverse planar flat plate member parallel to said 1 first member and dividing said tank into an intermediate chamber thereabove and a lower chamber therebeneath; an inlet for admitting liquid into said upper chamber and an outlet for discharging said liquid from said lower chamber; conduit means for establishing fluid communication between said upper chamber and said intermediate:

chamber and between said intermediate chamber and said lower chamber; valve means interposed in said conduit means for opening communication between said upl per chamber and said intermediate chamber while closi ing communication between said intermediate chamber and said lower chamber, and for closing communication between said upper chamber and said intermediate chamber while opening communication between said intermediate chamber and said lower chamber; means responsive to the level of liquid in said intermediate chamber for operating said valve means whereby said intermediate chamber is opened to communication with said upper chamber causing liquid to flow into said intermediate chamber, and subsequently opened to communication with said lower chamber to drain said intermediate chamber; and counter means for counting the 1 number of times said intermediate chamber is filled.

2. An automatic custody transfer system according to claim 1 wherein the volume of said upper, chamber is at least one and one-half times the volume of said'intermediate chamber.

3. An automatic custody transfer system according to claim 1 wherein said liquid level responsive means comprises an electric control system including liquid level responsive switches, cam means and a rotary motor for actuating said cam means; and circuit means for. controlling said valve means operation.

4. An automatic custody transfer system according to claim 3 wherein said counter means is driven directly, by said rotary motor.

5. An automatic custody transfer system comprising, a cylindrical tank; a pair of transverse, steeply sloping, plate members, parallel to one another and dividing said tank into three fluid-tight chambers comprising an upper chamber; an intermediate chamber and a lower chamber; said steep slope being sufficient to form a Seraphin neck structure with the side of said tank adjacent to the upper edge of said plate members; an inlet for admitting liquid into said upper chamber near the top thereof and an outlet for discharging liquid from the lower part of said lower chamber; conduit means for placing the lower portion of said upper chamber in fluid communication with:

said intermediate chamber and said lower chamber,

and for opening communication between said inter mediate chamber and said lower chamber while closing communication between said upper chamber and said intermediate chamber; first switch means responsive to a high level of liquid in said intermediate chamber; second switch means responsive to a low level of liquid in said intermediate chamber; actuating means responsive to said first and second switch means for operating said valve means to fill and drain said intermediate chamber whereby said valve means is actuated for opening communication between said upper chamber and said intermediate chamber causing liquid to flow into said intermediate chamber, and subsequently opening communication between said intermediate chamber and said lower chamber causing liquid to drain from said intermediate chamber; and counter means actuated by said actuating means for counting the number of times said intermediate chamber is filled and emptied.

6. An automatic custody transfer system according to claim wherein said actuating means comprises electric circuit means, cam means, and a rotary electric motor connected to drive said cam means; said counter means being directly driven by said rotary electric motor.

7. An automatic custody transfer system according to claim 5 wherein the volume of said upper chamber is at least one and one-half times the volume of said intermediate chamber.

8. An automatic custody transfer system comprising a cylindrical tank; a pair of parallel, transverse, steeply sloping flat planar plate members dividing said tank into three fluid-tight chambers comprising an upper chamber, an intermediate chamber and a lower chamber; the slope of said flat members being sufficient to create a Seraphin neck between the upper edge of each member and the adjacent side of said tank; an inlet for admitting liquid into said upper chamber near the top thereof and an outlet for discharging liquid from the lower part of said lower chamber; conduit means for placing the lower portion of said upper chamber in fluid communication with the lower portion of said intermediate chamber and for placing the lower portion of said intermediate chamber in fluid communication with said lower chamber; poweractuated valve means interposed in said conduit means for opening communication between said upper and said intermediate chamber while closing communication between said intermediate chamber and said lower chamber, and for opening communication between said intermediate chamber and said lower chamber while closing communication between said upper chamber and said intermediate chamber; a first float chamber opening from near the top of said intermediate chamber and extending upwardly therefrom; first liquid level responsive switch means positioned in said float chamber and above the full level of liquid in said intermediate chamber; a second float chamber opening from below the bottom of said intermediate chamber and having a principal discharge line into said lower chamber, said principal discharge line having the discharge end thereof located above the float level of said second float chamber; a restricted discharge line connecting the bottom of said second float chamber with said lower chamber, and a short cycle preventing valve in said restricted line; second liquid level responsive switch means positioned in said second float chamber at at point below the full drained condition of said intermediate chamber; electric circuit means operatively responsive to the operation of said first and second liquid level responsive switch means for operating said valve means to fill and empty said intermediate chamber whereby said valve means is actuated for opening communication between said upper chamber and said intermediate chamber causing liquid to flow into said intermediate chamber, and subsequently establishing communication between said intermediate chamber and said lower chamber causing liquid to drain from said intermediate cham her; a rotary electric motor energized by said electric circuit means; and counter means driven by said motor.

for recording the number of times said intermediate chamber is filled and emptied.

9. An automatic custody transfer system according to claim 8 wherein the volume of said upper chamber is at least one and one-half times the volume of said intermediate chamber.

10. An automatic custody transfer system according to claim 9 further including cam means driven by said rotary motor; and additional switch means actuated by said cam means and connected into said electric circuit means.

References Cited by the Examiner UNITED STATES PATENTS 1,696,512 12/1928 White 73310 X 2,831,350 4/1958 Banks et al 73224 X 2,966,798 1/ 1961 Smith 73224 2,977,796 4/1961 Pope et a1. 73219 2,995,139 8/1961 Remke et a1. 73224 X 3,023,618 3/ 1962 Franklin et a1 73224 RICHARD C. QUEISSER, Primary Examiner. 

5. AN AUTOMATIC CUSTODY TRANSFER SYSTEM COMPRISING, A CYLINDRICAL TANK; A PAIR OF TRANSVERSE, STEEPLY SLOPING, PLATE MEMBERS, PARALLEL TO ONE ANOTHER AND DIVIDING SAID TANK INTO THREE FLUID-TIGHT CHAMBERS COMPRISING AN UPPER CHAMBER; AN INTERMEDIATE CHAMBER AND A LOWER CHAMBER; SAID STEEP SLOPE BEING SUFFICIENT TO FORM A SERAPHIN NECK STRUCTURE WITH THE SIDE OF SAID TANK ADJACENT TO THE UPPER EDGE OF SAID PLATE MEMBERS; AN INLET FOR ADMITTING LIQUID INTO SAID UPPER CHAMBER NEAR THE TOP THEREOF AND AN OUTLET FOR DISCHARGING LIQUID FROM THE LOWER PART OF SAID LOWER CHAMBER; CONDUIT MEANS FOR PLACING THE LOWER PORTION OF SAID UPPER CHAMBER IN FLUID COMMUNICATION WITH THE LOWER PORTION OF SAID INTERMEDIATE CHAMBER AND FOR PLACING THE LOWER PORTION OF SAID INTERMEDIATE CHAMBER AND FOR IN FLUID COMMUNICATION WITH SAID LOWER CHAMBER; VALVE MEANS INTERPOSED IN SAID CONDUIT MEANS FOR OPENING COMMUNICATION BETWEEN SAID UPPER CHAMBER AND SAID INTERMEDIATE CHAMBER WHILE CLOSING COMMUNICATION BETWEEN SAID INTERMEDIATE CHAMBER AND SAID LOWER CHAMBER AND FOR OPENING COMMUNICATION BETWEEN SAID INTERMEDIATE CHAMBER AND SAID LOWER CHAMBER WHILE CLOSING COMMUNICATION BETWEEN SAID UPPER CHAMBER AND SAID INTERMEDIATE CHAMBER; FIRST SWITCH MEANS RESPONSIVE TO A HIGH LEVEL OF LIQUID IN SAID INTERMEDIATE CHAMBER; SECOND SWITCH MEANS RESPONSIVE TO A LOW LEVEL OF LIQUID IN SAID INTERMEDIATE CHAMBER; ACTUATING MEANS RESPONSIVE TO SAID FIRST AND SECOND SWITCH MEANS FOR OPERATING SAID VALVE MEANS TO FILL AND DRAIN SAID INTERMEDIATE CHAMBER WHEREBY SAID VALVE MEANS IS ACTUATED FOR OPENING COMMUNICATION BETWEEN SAID UPPER CHAMBER AND SAID INTERMEDIATE CHAMBER CAUSING LIQUID TO FLOW INTO SAID INTERMEDIATE CHAMBER, AND SUBSEQUENTLY OPENING COMMUNICATION BETWEEN SAID INTERMEDIATE CHAMBER AND SAID LOWER CHAMBER CAUSING LIQUID IN DRAIN FROM SAID INTERMEDIATE CHAMBER; AND COUNTER MEANS ACTUATED BY SAID ACTUATING MEANS FOR COUNTING THE NUMBER OF TIMES SAID INTERMEDIATE CHAMBER IS FILLED AND EMPTIED. 